Hamed Elham O, Abdel-Aal Amal M, Din Amal K Norel, Atia Mervat M A
Egypt J Immunol. 2013;20(2):1-10.
Many cellular, preclinical and observational studies support a role of vitamin D in pathogenesis of type-1 diabetes mellitus (DM). The vitamin D receptor (VDR) locus has been studied in different populations for association with susceptibility to immune-mediated diseases, but with inconsistent findings in type-1 DM. This study aimed to investigate vitamin D status in patients with type-1 DM. We examined the frequency of VDR Fokl (rs10735810) gene polymorphism, and its association with serum 25-hydroxyvitamin D (25(OH) D) level in Egyptian patients with type-1 DM. 132 children with type-1 DM and 40 age and sex matched healthy control subjects were studied. VDR Fokl polymorphism was assessed using polymerase chain reaction and restriction fragment length polymorphism (RFLP) analysis. Diabetic children demonstrated lower circulating levels of 25(OH) D than the controls (13.4 +/- 7.6 vs 32.1 +/- 3.8ng/ml) (P < 0.01). Patients with deficient 25(OH) D showed lower calcium levels and higher HbA1c% than those with sufficient levels (8.1 +/- 2.1 versus 9.1 +/- 1.6 mg/dl & 9.9 +/- 2.5 versus 8.1 +/- 1.4%, respectively (P < 0.05). There was no significant difference in the genotype distribution or the allele frequencies of VDR Fokl between patients and controls. The odds ratio (OR) was 1.08 (P = 0.76), and the 95% confidence interval (CI) ranged from 0.64-1.85. The diabetic carriers of the ff genotype showed low serum levels of 25(OH) D and calcium when compared with the carriers of the F allele (9.1 +/- 4.4 vs 13.1 +/- 7 and 13.9 +/- 6.09 ng/ml & 8.1 +/- 2.1 vs 9.1 +/- 1.1 and 9.3 +/- 1.2 mg/dl, respectively) (P < 0.05). In conclusion, 84.8% of children with type-1 DM have low circulating levels of 25(OH) D. These patients have poor glycemic control (56.06%) than those with sufficient levels of 25(OH) D. Fokl polymorphism of VDR gene is associated with vitamin D deficiency but has no significant role in susceptibility to type-1 diabetes.
许多细胞、临床前和观察性研究均支持维生素D在1型糖尿病（DM）发病机制中发挥作用。维生素D受体（VDR）基因座已在不同人群中进行研究，以探讨其与免疫介导疾病易感性的关联，但在1型糖尿病中的研究结果并不一致。本研究旨在调查1型糖尿病患者的维生素D状态。我们检测了埃及1型糖尿病患者中VDR Fokl（rs10735810）基因多态性的频率及其与血清25-羟基维生素D（25(OH)D）水平的关联。研究对象为132例1型糖尿病儿童及40例年龄和性别匹配的健康对照者。采用聚合酶链反应和限制性片段长度多态性（RFLP）分析评估VDR Fokl多态性。糖尿病儿童的25(OH)D循环水平低于对照组（13.4±7.6 vs 32.1±3.8ng/ml）（P<0.01）。25(OH)D缺乏的患者比水平充足的患者血钙水平更低，糖化血红蛋白（HbA1c）百分比更高（分别为8.1±2.1对9.1±1.6mg/dl和9.9±2.5对8.1±1.4%）（P<0.05）。患者与对照组之间VDR Fokl的基因型分布或等位基因频率无显著差异。优势比（OR）为1.08（P=0.76），95%置信区间（CI）为0.64-1.85。与F等位基因携带者相比，ff基因型的糖尿病携带者血清25(OH)D和钙水平较低（分别为9.1±4.4对13.1±7和13.9±6.09ng/ml；8.1±2.1对9.1±1.1和9.3±1.2mg/dl）（P<0.05）。总之，84.8%的1型糖尿病儿童25(OH)D循环水平较低。这些患者的血糖控制情况（56.06%）比25(OH)D水平充足的患者差。VDR基因的Fokl多态性与维生素D缺乏有关，但在1型糖尿病易感性中无显著作用。
